In a gas turbine, air pressurized in a compressor is mixed with fuel in a combustor to generate combustion gas that is a high-temperature fluid, and this combustion gas is introduced into a combustion gas flow passage of a turbine in which vanes and blades are alternately installed. The gas turbine rotates the blades and a rotor by the combustion gas flowing through the combustion gas flow passage. Thus, the gas turbine outputs the energy of the combustion gas as rotary energy, and imparts a rotary driving force to the compressor and a generator.
A clearance is provided between a transition piece of the combustor and a shroud of a first-stage vane of the turbine to prevent contact therebetween to thermal expansion. In this clearance, a seal member is provided to prevent casing air from leaking into the combustion gas flow passage (e.g., Japanese Patent Publication No. 2009-167905).
The surfaces of components of the gas turbine exposed to the combustion gas have a thermal barrier coating (TBC) applied thereto as a heat-resistant coating to enhance the heat resistance. This thermal barrier coating is applied to those regions that reach high temperatures by being exposed to the combustion gas. The thermal barrier coating is applied not only to a gas path surface facing the combustion gas flow passage, but also to a lateral wall surface intersecting with the gas path surface, on the side of the surface closer to the combustion gas flow passage.